Latest revision as of 11:39, 28 October 2020

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Concept Map

[maximize][fold]

Textbook

To add textbook links, please follow these instructions to: (Click to create the subpage)

Additional information

Useful websites

Cavendish experiment - This link gives a simple sketch of the Cavendish experiment.

This website demonstrates the set-up of the Cavendish experiment.

This is a college lecture by Prof Walter Levin explaining gravitation. Click here to see the video.
Conceptual Physics
Physics Classroom

Reference Books

The following textbooks are good references

Conceptual Physics, Paul Hewitt, 10th Edition
Physics for Scientists and Engineers, Douglas C. Giancoli, 3rd Edition
Resnick & Halliday with Jearl Walker, 8th Edition
NCERT Class 9 textbook Motion
NCERT Class 9 textbook Laws of Motion
NCERT Class 9 textbook Gravitation

Teaching Outlines

Concept #1 - Nature of Gravitational Force

Learning objectives

Inertial and Gravitational Property of Mass
Idea of a force field and that forces can act at a distance. The distance over which the effect of a force can be felt is called its field.
Gravitational force acts over a distance through a field and is one of the four fundamental forces
Gravitational force is a very small force

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

Mass has two aspects – inertial and gravitational. We are familiar with mass; it is an intrinsic property of matter. An intrinsic property is something that cannot be separated from the object. The mass of an object can be understood in terms of its gravitational aspect and inertial aspect. The intrinsic property of matter which makes it resist change is what we have called as mass. But this same mass possesses another property – the ability to “attract” mass. This we call the gravitational aspect. The gravitational aspect of the mass is responsible for the attractive force between two masses. The gravitational aspect is what makes masses interact with one another.

Gravitation is a fundamental force. Gravitational force, or gravity, is the force by which physical bodies attract each other with a force directly proportional to their mass and inversely proportional to the square of the distance between them. This is one of the four fundamental forces in nature. Gravity is the force which makes masses interact with one another. Gravitational force is mutually attractive. Another fundamental force is the electromagnetic force, due to another intrinsic property of matter – charge. These forces are due to charges possessed by an object and their movement.
Strong and weak nuclear forces are other fundamental forces that act within the nucleus of an atom, holding it together. These forces however act only at the subatomic level. Above the atomic level, gravitational and electromagnetic forces can satisfactorily explain all events.

Concept #2 - Newton's law of universal gravitation

Learning objectives

Gravitational Force is small
The importance of inverse square law

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. Click on the links below to read more.

Activity No # 1 Demonstration of the gravitational force

Click to Comment

Estimated Time - 45 minutes
Materials/ Resources needed
Prerequisites/Instructions, if any
Multimedia resources
Website interactives/ links/ simulations

Click here for PhET simulation

Process (How to do the activity)

Open the simulation
Work with the simulation, change the parameters and discuss the following questions o

Developmental Questions (What discussion questions)

When $m_{1}$ is moved towards $m_{2}$ what is the the force on each sphere?
What is the direction and magnitude of the force?
When the spheres are moved towards each other, does the force increase or decrease?
What is this due to? (Inverse square law)

Evaluation (Questions for assessment of the child)

If the gravitational force is the same for both objects, why do we see the apple falling but not the ground moving up?
What can you say about the magnitude of gravitational force?

Question Corner

If you were to go inside a mine, deep into the Earth will the gravitational force increase or decrease?
If there was a hollow channel through the centre of the earth and if you drop a ball inside, how would the ball move?

Activity No #

Click to Comment

Estimated Time
Materials/ Resources needed
Prerequisites/Instructions, if any
Multimedia resources
Website interactives/ links/ simulations
Process (How to do the activity)
Developmental Questions (What discussion questions)
Evaluation (Questions for assessment of the child)
Question Corner

Project Ideas

Fun corner

Usage

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 |style="width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
-[http://www.karnatakaeducation.org.in/KOER/en/index.php/Science:_History The Story of Science]
+[http://karnatakaeducation.org.in/KOER/en/index.php/Science:_History The Story of Science]
-|style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|[http://www.karnatakaeducation.org.in/KOER/en/index.php/Science:_Philosophy Philosophy of Science]
+|style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|[http://karnatakaeducation.org.in/KOER/en/index.php/Science:_Philosophy Philosophy of Science]
 |style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
-[http://www.karnatakaeducation.org.in/KOER/en/index.php/Science:_Pedagogy Teaching of Science]
+[http://karnatakaeducation.org.in/KOER/en/index.php/Science:_Pedagogy Teaching of Science]
 |style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
-[http://www.karnatakaeducation.org.in/KOER/en/index.php/Science:_Curriculum_and_Syllabus Curriculum and Syllabus]
+[http://karnatakaeducation.org.in/KOER/en/index.php/Science:_Curriculum_and_Syllabus Curriculum and Syllabus]
 |style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
-[http://www.karnatakaeducation.org.in/KOER/en/index.php/Science:_Topics Topics in School Science]
+[http://karnatakaeducation.org.in/KOER/en/index.php/Science:_Topics Topics in School Science]
 |style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
-[http://www.karnatakaeducation.org.in/KOER/en/index.php/Textbooks#Science_-_Textbooks Textbooks]
+[http://karnatakaeducation.org.in/KOER/en/index.php/Textbooks#Science_-_Textbooks Textbooks]
 |style=" width:10%; border:none; border-radius:5px;box-shadow: 5px 5px 5px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
-[http://www.karnatakaeducation.org.in/KOER/en/index.php/Science:_Question_Papers Question Bank]
+[http://karnatakaeducation.org.in/KOER/en/index.php/Science:_Question_Papers Question Bank]
 |}
 While creating a resource page, please click here for a resource creation [http://karnatakaeducation.org.in/KOER/en/index.php/Resource_Creation_Checklist '''checklist''']
 = Concept Map =
-<mm>[[Universal_Law_of_Gravitation.mm|Flash]]</mm>
+[[File:Universal_Law_of_Gravitation.mm|Flash]]
 __FORCETOC__
 = Textbook =
@@ Line 27: / Line 27: @@
 = Additional information =
 ==Useful websites==
+#Cavendish experiment - This link gives a simple sketch of the Cavendish experiment.
+This [http://sciencedemonstrations.fas.harvard.edu/icb/icb.do?keyword=k16940&pageid=icb.page80669&pageContentId=icb.pagecontent277503&state=maximize&view=view.do&viewParam_name=indepth.html website] demonstrates the set-up of the Cavendish experiment.
+#[[Image:Walter-Levin.png|80px|left]]This is a college lecture by Prof Walter Levin explaining gravitation.  Click [http://upload.wikimedia.org/wikipedia/commons/9/91/Newtonslawofgravity.ogg here] to see the video.<br><br><br><br>
+#[http://www.conceptualphysics.com/ Conceptual Physics]
+#[http://www.physicsclassroom.com Physics Classroom]
 ==Reference Books==
+The following textbooks are good references
+#Conceptual Physics, Paul Hewitt, 10th Edition
+#Physics for Scientists and Engineers, Douglas C. Giancoli, 3rd Edition
+#Resnick & Halliday with Jearl Walker, 8th Edition
+#NCERT Class 9 textbook [http://ncert.nic.in/NCERTS/textbook/textbook.htm?iesc1=8-14 Motion]
+#NCERT Class 9 textbook [http://ncert.nic.in/NCERTS/textbook/textbook.htm?iesc1=9-14 Laws of Motion]
+#NCERT Class 9 textbook [http://ncert.nic.in/NCERTS/textbook/textbook.htm?iesc1=10-14 Gravitation]
 = Teaching Outlines =
@@ Line 47: / Line 60: @@
 * Strong and weak nuclear forces are other fundamental forces that act within the nucleus of an atom, holding it together. These forces however act only at the subatomic level. Above the atomic level, gravitational and electromagnetic forces can satisfactorily explain all events.
 <br><br>
-===Activity No # 1 - Discussion about mass ===
-{| style="height:10px; float:right; align:center;"
-|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
-''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
-|}
-* '''Estimated Time''' - 30 minutes
-* '''Materials/ Resources needed'''
-* '''Prerequisites/Instructions, if any'''
-* '''Multimedia resources'''<br>
-{{#widget:YouTube|id=QkCWoRGZLyI}}<br>
-'''This video describes the inertial property of mass'''
-* '''Website interactives/ links/ simulations'''
-* '''Process (How to do the activity)'''<br>
-#Let the students watch the video
-#Ask them to write situations where they have faced inertia
-* '''Developmental Questions (What discussion questions)'''
-#When do we say something has inertia? (When it does not change its position)
-#What does inertia do? (Resists change)
-#Does it depend on size of the object? (Yes/ No/ Not always)
-#If not on size, what does it depend on? (It depends on how much matter ther?e is - mass)
-#When we observe inertia, we can say object has mass
-* '''Evaluation (Questions for assessment of the child)'''
-#Does inertia increase with size?
-#Will an object have inertia when it moves?
-* '''Question Corner'''
-#How can I tell that an object has mass or not?
-===Activity No # ===
-{| style="height:10px; float:right; align:center;"
-|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
-''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
-|}
-* '''Estimated Time'''
-* '''Materials/ Resources needed'''
-* '''Prerequisites/Instructions, if any'''
-* '''Multimedia resources'''
-* '''Website interactives/ links/ simulations'''
-* '''Process (How to do the activity)'''
-* '''Developmental Questions (What discussion questions)'''
-* '''Evaluation (Questions for assessment of the child)'''
-* '''Question Corner'''
 ==Concept #2 - Newton's law of universal gravitation==
@@ Line 96: / Line 65: @@
 #Gravitational Force is small
 #The importance of inverse square law
-[[:File:gravity-force-lab-screenshot.png]]
-=== Activity 1 Use the following simulation for a demonstration of the gravitational force ===
-[[Image:gravity-force-lab-screenshot.png|Gravity Force Lab]]
-{| border="1"
-|-
-|Click to Run
-|}
-[http://phet.colorado.edu/en/simulation/gravity-force-lab Click here for PhET simulation]
-<br><br>
 ===Notes for teachers===
 ''These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.''
-[Newton's Law of Gravitation]
+Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. Click on the links below to read more.
-''Newton's Law of Gravitation''
-Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. This force acts along the line joining the two particles. Separately it was shown that large spherically symmetrical masses attract and are attracted as if all their mass were concentrated at their centres.
-For non-symmetric objects, the masses will be concentrated a the centre of mass and the distance between these centres is what will be taken as the distance
-[[Image:Gravitation%20for%20wiki_html_39d0b1a1.png|200px]] <br>
-F = G m_1*m_2 / r^2
-* F is the force between the masses,
-* m1 is the first mass,
-* m2 is the second mass,
-* G is the gravitational constant
-* r is the distance between the masses
-In SI units, Force, F is measured in newtons (N), masses m1 and m2 are measured in kilograms (kg), and the distance between the masses is measured in metres.
+#[[Newton's Law of Gravitation]]
-<br><br>
+#[[Inverse Square Law]]
+#[[Law of gravitation and relativity]]
+===Activity No # 1 Demonstration of the gravitational force ===
-''Universal Gravitational Constant''
-The magnitude of G is identical to the magnitude of the force between a pair of 1-kg masses that are 1 metre apart and has been experimentally determined to be equal to 6.674×10−11N m2 kg−2. The value of the constant G was first accurately determined from the results of an experiment conducted by the British scientist Henry Cavendish in 1798. He accomplished by measuring the tiny force between lead masses with an extremely sensitive torsion balance. This small magnitude indicates that the gravitational force is an extremely weak force.
-This experiment was also the first test of Newton's theory of gravitation between masses in the laboratory. It took place 111 years after the publication of Newton's Principia and 71 years after Newton's death, so none of Newton's calculations could use the value of G; instead he could only calculate a force relative to another force.
-<br><br>
-''Inverse Square Law''
-Newton's law of gravitation resembles Coulomb's law of electrical forces, which is used to calculate the magnitude of electrical force between two charged bodies. Both are inverse-square laws, in which force is inversely proportional to the square of the distance between the bodies. Coulomb's Law has the product of two charges in place of the product of the masses, and the electrostatic constant in place of the gravitational constant. One important point of comparison is that the the value of the constant in Coulomb's law (for force between two charges of 1C separated by a distance of 1 m) is of the order of magnitude 109, which is 1000 billion billion times more than the gravitational constant. This means that the electrostatic force is a much stronger force than the gravitational force.
-''Why should this be so?''
-[[Image:Gravitation%20for%20wiki_html_m1eae328e.png]] <br>
-When we consider the gravitational field of a mass, we consider it to be a point mass. For any object, this can be approximated and we can find that this holds true. Some standard physics textbooks will give us this mathematical derivation as well. If there is a point mass and there is a field originating from it, the field must originate uniformly in all directions. If we imagine enclosing this point mass in a sphere and if we represent the field by field lines (called flux), we can visualize that these field lines must pass through uniformly throughout the surface area of the sphere. Now we can use simple geometry to explain why the field varies with inverse square of the distance. For the same area, the number of flux lines that will cut through a given area will reduce the farther the area is from the source. If we consider the area as a square on the surface of a sphere, the density of flux lines that will cut through the surface of a sphere is inversely proportional to the square of the distance from the source as the surface area of a sphere increases with the square of the radius. Hence the field strength will vary inversely with the square of the distance.
-<br><br>
-''Law of gravitation and relativity''
-Newton's law has since been superseded by Einstein's theory of general relativity, but it continues to be used as it is, as an excellent approximation of the effects of gravity. Gravitational force acts at a distance. The properties of the space surrounding any massive body can be considered to be altered in such a way that another massive body in this region experiences a force. This alteration of space is a gravitational field. Einstein perceived a gravitational field as a geometrical warping of four dimensional space and time; masses “bend” the space around them. Gravity is the property of matter that possesses mass that causes a force of attraction to exist between any two particles in space.
-<br>
-===Activity No # ===
 {| style="height:10px; float:right; align:center;"
 |<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
-''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
+''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 |}
-* '''Estimated Time'''
+* '''Estimated Time''' - 45 minutes
 * '''Materials/ Resources needed'''
 * '''Prerequisites/Instructions, if any'''
 * '''Multimedia resources'''
 * '''Website interactives/ links/ simulations'''
+[[Image:gravity-force-lab-screenshot.png|200px]]
+[http://phet.colorado.edu/en/simulation/gravity-force-lab '''Click here for PhET simulation''']
+<br><br>
 * '''Process (How to do the activity)'''
+#Open the simulation
+#Work with the simulation, change the parameters and discuss the following questions o
 * '''Developmental Questions (What discussion questions)'''
+#When <math>m_1</math> is moved towards <math>m_2</math> what is the the force on each sphere?
+#What is the direction and magnitude of the force?
+#When the spheres are moved towards each other, does the force increase or decrease?
+#What is this due to? (Inverse square law)
 * '''Evaluation (Questions for assessment of the child)'''
+#If the gravitational force is the same for both objects, why do we see the apple falling but not the ground moving up?
+#What can you say about the magnitude of gravitational force?
 * '''Question Corner'''
+#If you were to go inside a mine, deep into the Earth will the gravitational force increase or decrease?
+#If there was a hollow channel through the centre of the earth and if you drop a ball inside, how would the ball move?
 ===Activity No # ===
 {| style="height:10px; float:right; align:center;"
 |<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
-''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
+''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 |}
 * '''Estimated Time'''

Difference between revisions of "Universal Law of Gravitation"

Latest revision as of 11:39, 28 October 2020

Contents

Concept Map

Textbook

Additional information

Useful websites

Reference Books

Teaching Outlines

Concept #1 - Nature of Gravitational Force

Learning objectives

Notes for teachers

Concept #2 - Newton's law of universal gravitation

Learning objectives

Notes for teachers

Activity No # 1 Demonstration of the gravitational force

Activity No #

Project Ideas

Fun corner

Navigation menu

Search